That’s according to a new report from the Blue Cross Blue Shield Association, for which analysts assessed the BCBS Health Index built from billions of claims for more than 41 million commercially insured Americans annually.

The index, which quantifies how more than 200 diseases and conditions impact quality of life, showed that major depression is the second most significant condition on overall health in America. The first is hypertension, or high blood pressure.

According to the report, those diagnosed with major depression are nearly 30 percent less healthy on average than those without the condition. Such a decrease in overall health may mean a loss of nearly 10 years of healthy life for both men and women.

More than nine million commercially insured Americans in the index are affected by major depression. The rate of diagnosis in the country is 4.4 percent. But while diagnoses are up 33 percent since 2013 overall, the rate is even higher among teens and young adults − 47 percent. For teen girls, specifically, the rate has risen by 65 percent.

"The high rates for adolescents and millennials could have a substantial health impact for decades to come," Trent Haywood, senior vice president and chief medical officer for BCBSA, said in a statement. "Further education and research is needed to identify methods for both physicians and patients to effectively treat major depression and begin a path to recovery and better overall health."

Analysts also found that overall, women are more than twice as likely as men to be diagnosed with major depression (6 percent compared to 2.8 percent, respectively).

Geographically, 49 of the 50 states saw rising diagnosis rates between 2013 and 2016. Hawaii was the only state that experienced a slight decline (a rate of less than 2 percent). Communities in New England, the Pacific Northwest and areas throughout the South and Midwest had higher rates of major depression compared to the rest of the country.

Rhode Island had the highest diagnosis rate with 6 percent. However, the authors noted that differences in efforts to screen for major depression can result in varying diagnoses rates across states.

“While major depression is the second most impactful health condition for the nation, it is complicated by an increased likelihood of overlapping diagnoses of other chronic, behavioral health and pain-related conditions,” authors of the report wrote.

In fact, of the 9 million Americans diagnosed with major depression in 2016, only 15 percent were diagnosed with depression alone. Eighty-five percent, according to the analysis, were diagnosed with an additional health condition.

In addition to a lower quality of life, those diagnosed with major depression are more likely to use more healthcare services, resulting in more than twice the spending.

It’s important to note that the report’s findings, based on people with BCBS commercial health insurance, are likely an underestimate. Most Americans are covered by a commercial health plan, but many who report symptoms of depression say they have not been diagnosed or received treatment for the condition.

According to the World Health Organization, more than 300 million people of all ages suffer from depression, and it’s the leading cause of disability worldwide.